<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    //浅拷贝只是拷贝一层，更深层次对象级别的只拷贝引用
    //深拷贝拷贝多层，每一级别的数据都会拷贝
    var obj = {
      id:1,
      name:'andy',
      msg:{
        age:18
      }
    };
    var o = {};
    // for(var k in obj){
    //   //k 属性名 obj[k] 属性值
    //   o[k] = obj[k];
    // }
    // console.log(o);
    // o.msg.age = 20;
    // console.log(obj);
    console.log('--------------');
    Object.assign(o,obj);
    console.log(o);
    o.msg.age = 20;
    console.log(obj);
  </script>
</body>
</html>